The janitorial supply company made mops, brooms, scrubbing and polishing pads.
Investigators are expected to focus on what chemicals were in the building that set off at least one explosion.
Henderson fire Chief Danny Wilkinson said the preliminary investigation into the cause of the fire points to a welding torch.
"We had some interviews going on with some of the employees, and the SBI agent and ATF agent are doing a walkaround, looking inside in the area where the welding was supposedly taking place," he said.
As many as 100 employees were safely evacuated from the building which burned through the night.